1. Field of the Invention
The present invention relates to a contact, and especially to a fine pitch contact for use with a zero insertion force (ZIF) socket.
2. Description of Prior Art
As computer functions continue to expand, an IC package, such as a Central Processing Unit (CPU), requires an increasing number of memory processing units, thus pins of the IC package are arranged to be more compact. Correspondingly, a socket for coupling with the IC package has more contacts. A conventional contact used in a ZIF socket related to the present invention is disclosed in U.S. Pat. No. 4,988,310 and in Taiwan Patent Application Nos. 83203222, 83208396, 83212081 and 83212046.
Referring to FIGS. 1A and 1B, a conventional contact 1 used in a ZIF socket 7 comprises a base 12 for being fixed in the socket 7, a tail 13 downwardly extending from the base 12 for electrically connecting with a printed circuit board (not shown), a mating portion 14 formed at a free end thereof, and a beam 15 interconnecting the base 12 and the mating portion 14. The mating portion 14 is a cantilevered beam and includes an engaging section 144 and a lead-in section 142 outwardly extending from the engaging section 144 distanced from the beam 15. The engaging section 144 is adapted for engaging with a CPU pin 2 to implement an electrical connection therebetween. When the CPU pin 2 is moved in a direction as indicated by the arrow "A" to contact the engaging section 144, the lead-in section 142 deforms to exert a normal force on the pin 2 and guides the CPU pin 2 to connect with the engaging section 144.
The mating portion 14 of the conventional contact 1 has a significant length L.sub.1 due to the provision of the outwardly extending lead-in section 142. The mating portion 14 usually extends within and therefore occupies a certain portion of a corresponding passageway 8 defined in the socket 7. Due to the trend of miniaturization, the passageways 8 of the socket 7 are required to have smaller dimension. However, the mating portion 14 of the conventional contact 1 remains to occupy a significant portion of the corresponding passageway 8 of the socket 7, which prevents the length D.sub.1 of the passageway 8 from being reduced. Thus, the conventional contact 1 cannot satisfy requirements of an IC package having more compact pins.